I see that danob dismissed,

colour monitor calibration [as] an utter waste of money

... and went on to say,

to be accurate what is the point of having just one part of the cailbration done

As I see it, we are talking about color and error(s) in the color ... and
management of those errors.

Yes, if you want absolute color accuracy, you must calibrate each step
of the process.

Does that mean that if you're not going to calibrate each step, that
you shouldn't fix the errors that you are able to fix?  ... does that mean
that if you know your monitor isn't properly calibrated (or even if you
just think it's out of calibration), that you shouldn't correct it?

Remember, monitor calibration affects everything you see on your PC
-- not just your own work, but everything you see. 

--
Martin